A valve assembly that can be employed in a variable camshaft timing (VCT) phaser assembly. The valve assembly includes a metal sleeve and a check valve. The check valve, in an implementation, has an integral construction with the metal sleeve. The integral construction has multiple designs, one of which includes an overmolded construction of the check valve with the metal sleeve. The valve assembly can also include a valve housing which, in the implementation of the VCT phaser assembly, is a center bolt.

A check valve for controlling the flow of a fluid into a variable camshaft timing phaser.

A variable cam timing phaser includes a housing disposed about an axis and having an inner housing surface defining a housing interior. The variable cam timing phaser includes a rotor moveable between an advance position and a retard position. The rotor includes a hub and a vane, with the rotor and the housing defining a chamber. The vane further defines the chamber into an advance chamber and a retard chamber. The variable cam timing phaser also includes a control valve assembly including a valve housing and a control piston. The variable cam timing phaser also includes a chamber biasing assembly disposed in one of the advance and the retard chambers and configured to bias the rotor into a predetermined position between the advance and the retard positions. The chamber biasing assembly includes a chamber piston, a chamber biasing member, and a chamber check valve.

An oil pressure actuated or torsion assisted phaser with a lock pin that has a position which shuts off communication between the advance and retard chambers and the front cam bearing and/or oil control valve, effectively acting as a shutoff valve and preventing leakage of oil from the advance and retard chambers. The prevention of leakage maintains oil in the phaser after engine shutdown. Additionally, by shutting off communication between the advance and retard chambers and the oil supply, the side load on the lock pin from the oil pressure torque on the rotor vanes during unlocking of the lock pin can be reduced or eliminated.

A phaser which has an offset or remote pilot valve added to the hydraulic circuit to manage a hydraulic detent switching function, in order to provide a mid-position lock for cold starts of the engine, either during cranking or prior to complete engine shutdown. The mid-position locking of the phaser positions the cam at an optimum position for cold restarts of the engine.

There is provided a variable valve timing system for an engine in which a cylinder head is fixed on a cylinder, and the cylinder head is suspended on a vehicle body frame, the variable valve timing system including: a variable valve device configured to change an opening and closing timing of a valve according to a hydraulic pressure; and an oil control valve. The vehicle body frame includes a main frame configured to laterally cover a rear side of the cylinder head and a down frame configured to laterally cover a front side of the cylinder head. In a side view of a vehicle, the oil control valve is detachably disposed on an outer surface of the engine below an area surrounded by the main frame, the down frame, and a lower surface of the cylinder head.

There is provided a variable valve timing system including: a variable valve device; an oil control valve configured to control a hydraulic pressure with respect to the variable valve device; an external pipe connecting a main gallery and the oil control valve; and a hydraulic pressure sensor configured to detect a hydraulic pressure in an oil path formed at the crankcase. The oil control valve is disposed on one side surface of the engine in the vehicle width direction. One end portion of the external pipe is connected to one side of the main gallery in the vehicle width direction. In a bottom view of a vehicle, the one end portion of the external pipe overlaps with the crankcase, and the hydraulic pressure sensor overlaps with the crankcase on one side of the one end portion of the external pipe in the vehicle width direction.

There is provided a variable valve timing system including: an intake side camshaft and an exhaust side camshaft disposed on a cylinder head; and a variable valve device attached to one end portion of the intake side camshaft. The accommodating wall on an exhaust side of the cylinder head is positioned more inward in a vehicle width direction than the accommodating wall on an intake side of the cylinder head. A first bolt for fixing the intake side of the cylinder head to a cylinder is disposed more inward in the vehicle width direction than the accommodating wall on the intake side. A second bolt for fixing the exhaust side of the cylinder head to the cylinder is disposed more outward in the vehicle width direction than the accommodating wall on the exhaust side.

There is provided a variable valve timing system for an engine in which a cam chain chamber is formed in a cylinder and a cylinder head, the variable valve timing system including: a variable valve device configured to change an opening and closing timing of a valve; an oil control valve configured to control a hydraulic pressure with respect to the variable valve device. The oil control valve is disposed on an outer surface of the cylinder, which is an outer wall of the cam chain chamber. An oil path enters the outer wall of the cam chain chamber from the oil control valve, and after extending toward a side of the cylinder head from a side of the cylinder, the oil path extends toward the variable valve device through an inner wall of the cam chain chamber through an oil pipe.

There is provided a variable valve timing system, including: a camshaft rotatably supported by a support wall of an engine; a variable valve device configured to advance or retard the camshaft by a hydraulic pressure; and an oil control valve. A thrust stopper is formed on an outer peripheral surface of the camshaft. A bearing surface of the support wall is formed with an advance groove through which oil for advancing the camshaft is to pass, a retard groove through which oil for retarding the camshaft is to pass, and an accommodation groove configured to accommodate the thrust stopper. At the bearing surface, the retard groove is positioned on one wall surface side of the support wall, the accommodation groove is positioned on the other wall surface side of the support wall, and the advance groove is positioned between the retard groove and the accommodation groove.